1. Field of the Invention
This invention relates to a molded product with excellent impact resistance comprising an acrylic polymer coagulated material with multiphase structure, an acrylic polymer coagulated material used for the manufacture thereof, a composition thereof, and a manufacturing process for preparing said acrylic polymer coagulated materials and said compositions thereof.
2. Description of Prior Art
Discontinuous dispersion of elastic rubbery phase in hard resin has been generally used to improve impact resistant properties of acrylic resin, styrene resin, vinyl chloride resin, etc. Introducing of diene type rubber has been generally applied, and introducing acrylic rubbers has also been used because of their outstanding weatherabilities.
As for modifier resins using acrylic rubbers, various polymers with multiphase structure wherein combination of soft phase and hard phase based on core/shell structure have been studied (Japanese Patent No. Sho 54-18298, Sho 55-27576, Sho 62-41241). Emulsion polymerization methods have been widely applied for producing said modifier resins, which need an isolating process for separating the polymer from the polymer latex. For this purpose, adding an inorganaic salt, such as aluminum chloride, magnesium sulfate, etc., adding an acid, such as sulfuric acid, etc., or spray drying etc. have been used. However, these methods have drawbacks such as fall in productivity and moldability, etc. because of the difficulties in handling characteristics caused by very fine powder state. Also molded products using these polymers have drawbacks such as degrading in optica properties by thermal coloration, in hydrothermal resistance shown as whitening when dipped in hot water, etc.
In order to improve the handling characteristics of a polymer, Japanese Patent Laid-open No. Sho 58-1742 shows that mixing a slurry of an impact modifier polymer and a slurry of hard inelastic polymer and then drying to control blocking at drying. However, the improvement in blocking by this method is not satisfactory and further no improvement was found in thermal coloration and in hydrothermal resistance when dipped in hot water.
In order to improve thermal coloration, Japanese Patent Laid-open No. Sho 61-108629 discloses a process comprising polymerizing with an emulsifier having a group selected from the group of consisting of --SO.sub.3 M, --COOM, and --SO.sub.3 M wherein M is sodium or potassium and isolating the formed polymer by the addition of an aqueous magnesium sulfate solution to the latex, and Japanese Patent Laid-open No. Sho 63-227606 discloses a process comprising polymerizing with an emulsifier having a group selected from the group consisting of --PO.sub.3 M.sub.2, and --PO.sub.2 M wherein M represents an alkali or an alkali earth element and isolating the formed polymer by the addition of an aqueous magnesium sulfate solution. Although some improvements have been recognized, but the level of improvement is not satisfactory. Also, the isolated polymers show inferior handling characteristics caused by very fine powder state, and no improvent was found in hydrothermal resistance.
Accordingly, it is an object of the present invention to provide a molded product comprising an acrylic polymer coagulated material having excellent characteristics in impact resistance, optical properties and hydrothermal reistance; an acrylic polymer coagulated material used for the manufacture thereof; a composition thereof; and a manufacturing process for preparing them.